1. Field of the Invention
The present invention relates to the field of transmitter-receiver telephone stations which are intended to be employed in two-way communication links without any intermediate management unit such as an exchange and which are in a standby-watch state over more or less long periods of time or, in other words, which await subsequent reception of a signal and, during these watch periods, are supplied intermittently in order to save power. The present invention is more particularly concerned with the control of means for saving power.
2. Description of the Prior Art
It is already a known practice to supply a station intermittently as long as it is in the standby-watch state. For technological reasons, it is preferable to have supply periods of relatively substantial length (at least of the order of one second) in the standby-watch state and consequently to have "non-supply" periods which are also of long duration (of the order of at least five seconds). These stations must be capable of calling each other. In order to achieve this aim, it is known to utilize the presence of a modulating signal in the signal received by the called station in order to operate a bell circuit or so-called ringer. However, this gives rise to disadvantages at the moment of completion of a conversation. Unless the users of the two connected telephone sets hang-up simultaneously, the bell circuit of the station which has "rung-off" first is closed as long as the other station has not rung-off.